Thomas dunlap



T. DUNLAP.

OAR

" A MMA XMMS@ i ATENT FFICE.

V-TIIOB'IAS DUNLAP, `OF TOLEDO, OHIO.

OAR.

SPECIFICATION forming part Aof Letters Patent No. 560,980, dated May 26,1896.

Application filed April 10, 1895. Serial No. 545,128. (No model.)

T0 all whom, it may concern:

Be it known that I, THOMAS DUNLAP, of Toledo, county of Lucas, and Stateof Ohio, have invented certain new and useful Iniprovements in Oars; andI do hereby declare -that the following is a full, clear, and exactdescription thereof, which will enable others skilled in the art towhich it appertains to make and usethe same, reference being had to theaccompanying drawings, and to the numerals of reference marked thereon,which form part of this specification. I

My invention relates to an improvement in oars, and has for its objectto construct an oar having a blade of greater resistance in front whenin action and less tendency to draw water after it than those heretoforein use.

The invention consists, broadly, in an oar having a blade with its frontface formed so as to represent a surface moldedon the lines of one-halfof the interior of a cylinder, the diameter of which equals the width ofthe blade and the axis of which is parallel to the center line of theshaft of the oar extended. Said front face along its whole length is asingle semicylindrical straight channel, not broken by ridge ordepression and not def lected by spoon curves, whereby when the oar isin action the water in front of it will be prevented from upward ordownward flow, thus securing increased leverage of the oar upon theoar-lock, and its upward flow will be free from friction of ridges,depressions, or spoon curves, thus facilitating its release when thestroke is being finished, and with a rear side molded on lines of equallength to the front face, parallel thereto, and so eX- tended as topresent in cross-section the eX- terior of an equilateral-pointed archlocated sufficiently in rear of the front face t-o insure stability.

'In the drawings, Figure l is a side elevation of the oar. Fig. 2 is aplan view showing the semicylindrical front face of the blade. Fig. 3 isa longitudinal vertical section of the blade on line X X of Fig. 2, andFig. 4L is a cross-section on lines Y Y of Fig. 2.

l on Figs. l and 2 designates the oar.

2 on Figs. l, 2, and 3 designates the blade.

3 on Fig. 3 designates the bottom line of the semicylindrical straightchannel in front of the blade 2, whereby a pull on the oar may be mademore effective than on an oar with a flat blade or a spoon-shaped one,whether its surface be divided by ridges or otherwise varied fromtheinterior surface of a half-cylinder secured in lines parallel to thecenter line of the shaft of the oar extended. The channel so constructedhas greater purchase on the water when a stroke is made by the rower,and the return of the oar in the water in front can be more easilyreleased than from any other device heretofore used in rowing.

The face of the blade 2 is seen on Fig. 2 to be smooth, single, anduniform, without ridges, corrugations, or spoon-shaped curves, and onFig. 3 the longitudinal lines of the channel in front of blade 2 areseen to be straight, uniform, unbroken, and parallel to the center lineof the shaft of the oar extended.

3 on Fig. 4 designates the line of the channel in front of the blade 2on the cross-section, which is seen to be a semicircle, and shows theshape of the front of the blade 2 to have but one transverse curve.

' 4 on Fig. 4 designates the outside line of the rear of blade 2 atcross-section, which is seen to be an equilateral-pointed arch and showsthe shape of the rear side of the blade 2.'

By reason of the formation of the rear side of blade 2 in shape of anequilateral-pointed arch, the oar in action leaves less vacuum behind itthan any device heretofore in use in rowing.

By reason of the formation of blade 2 as above described, I am enabledto combine great rigidity and strength with a minimum weight, and amaximum resistance by the water to forward stroke of the oar withminimum draft from vacuum in rear of the blade.

Vhat I claim is l. In an oar, a blade with its front face formed with asurface molded on the lines of one-half of the interior of a cylinder,the diameter of which equals the width of the blade, and the axis ofwhich is parallel to the center line of the shaft of the oar extended.

2. In an oar, a blade formed with the rear side molded on lineslongitudinally parallel to the longitudinal lines of the front face, andso drawn as to present in cross-section the outline of anequilateral-pointed arch.

As an article of manufacture, an oar lOO formed with a blade having astraight se1nicylindrical channel along its front side, and a ieai' sidemolded on lines longitudinally parallel to IL-he longitudinal lines ofthe front face, and so drawn as to present in crossseetion the outlineof an equilateial-pointed arch.

In testimony that I claim the foregoing as my own I hereby aiix mysignature in presence of two witnesses.

THOMAS DUNLAP.

lVitnesses II. VAN CAMPEN, Jr., ALICE E. CRooK.

